Pulse echo system



May 23, 1950 H. F. MAYER 2,509,007

PULSE ECHO SYSTEM Filed Feb. 13, 1946 A? C A A A A A Pfam/fa PM 55S ,4Z/Mam 420W/m Inventor:

Harry Ff Mayer,

H is Attorney Patented May 23, 1950 Afre-s v2,509,607 .PULSE Vicono susanna Harry 4li. Mayer, Schenectady, NKY., 'assigner to v"General Electric Company, *a *corpora-tion ol' New JYork n Y Y Application February 13, F1,946,3Serial ,N o. 647,272

v eciaims. (Cuers-1r) Myinvention relates 'to pulse echo systemsand fpjomt thereon. When the jpulse echo vsystexirjis f 'incre particularly to such systems adapted'todepointedinia spegcicdirection, 'the remote objects terminethe distance or range of remote objects shownonjthecathode `raytube 'screen appea'rras In one type of pulse echo `system the distance a single'lin'e of luminouspoints. However, the'ebto a remote object is 'indicated by the'position of 5 jecthaving distance corresponding to the time aiuminous point on a cathode ray tube screen delay ofthe fgate jpu'lses'isdisplaced'along'the jalongene'axisgenerally designated astherange vaizimuth axis and may readily be 'distinguished axis jand the azimuth of the remote Vobjectin/dijfrcmall others. *Ihisperformancemay'be,accum- A cated'bythe position :of the sam'e'lum'inouspoint Aplislied 'in a .cathode ray tube having' electin- -f'along an axis normal t'o the vfirst axis generally 10 ,.'staticdeiiectionby addingvoltage, corresponding designated ast-,he azimuth axis. Accurate m'ea- 'tothe "fgating pulses, 'to the'volta'ge applied to lsurement of .distance is provided by a series of the azimuth deiiectingplates .voltage pulses, known as gate pulses, generated Asis` well-Lknownin thepuls'e echo arl-therewthn the system and accurately delayed with're- J ceived pulses may eitherbe vdirect reiiection's, li..e.

spectfto'transmitted energy pulses. In one method 15 echoes, .ofthe transmitted pulses from ,a remote .of measuring the distance `to a remote object the jvobjegt, jor 'they may be pulses reqadiatedln 1regt pulses are Shown as a luminous spot lon VVsponse to the incident transmittedpulses byap- .the `cathode ray 'tube screen `at points along `the p'aratus at the `remote object. Therefore, Yvv'he're Yrange exis corresponding "to their 'time delay. the received pulse is .described in 'the idllowing .This luminous spot .may be movedto coincidence .20 spee'ineation and elaimsas a "reiiectedwor "eche" `With a luminous spot produced bypulses received pulse, lr where the .remote object ,is .described as imm a remote bjectandthe rangeef'that Object a v"reflecting object. .it is ,to be understood that 'determined `by observing lthe time delay of the k either .of fthese methods of ree-radiation isin- 1gate pulses. ylin some ylelllse echo systems,V the duded, "luminous spotcorresponding to vthe gate pulses v The novel features whichI believe to be char- .auimatCally placed ill CiCdenCe With `'011 acteristic of my linvention are set forth Withparspot corresponding to a remote object and held lticu'la'r'ityin the annended claims. yMy invention inthatpositiondespiterelativemotion of thesobitself, however, both as .to its organization :and

ject .and the pulse echo equipment. Hencefa `method .of .operation together .with further 6b- Sngle lspot is seen on the screen corresponding jectsandadvantages thereofmay bestvbesunder- Aite.the.combination of thelocallygenerated'"gate stood by reference ,to the following ,description .pulses ,and .the received signal pulses. ,takeninconnection withtlieaccompanying dravv- It is .an object of my invention to l(provide an ings in ywhich Fig. l vis adiagram indicating the Villpltoved method-ofgproducingfthelluminous spot rvarious signal pulses .within the .radar system;

indication on a cathode ray tube screen due to 'a 35 ,Fig. 2 lillustrates an embodiment of my invention vremote object having distance 4corresponding Ito and Figs. :3 and 4 show .the appearance 'of the thetime delay of the gatepulses of apulseecho cathodevray tube screen .under variousconditions v`,-system. of .opera-tion.

It is a further object of Vmy invention to .pro- In Fig. l `the various signals Within the yradar vide means of indicating the particular luminous 10 system ,are shown on .a single'time scale. fSweep 4spot on a vcathode ray tube screen due to a revoltageA consists of ase'iies of saw tooth Waves mote object having distance correspondingto the which .areused to deliecttherayof a cathoder`ay timedelay automatically maintained by the "g,ate device ,along the frange or vertical axis. .Curve vllIB Apulses of .a ,pulse echosystem. shoWsthesignal pulsespfrom the transmittercor- In addition, .it is an `object of my .invention rto responding .to the ,sweep o1 curve A, each .pulse p rovfide a means of indicating the luminous point taking place `at the instant voltage A starts :from on the 'cathode ray tube screen of a pulse `echo zero. -Curve .C shows the received .pulse signals, ,system due toa remote-object having distance cordue .to .reiiec'ted ,or reply energy, Vfrom ,a remote responding to the time delay of the gate pulses 'object thedisitance .of which is 4desired to be mea- ,ina manner which maybe observed by -the vop- .50 sured.y `These ,signalscorrespond with ,the transera'tor with a .minimum degree of confusion. vmitted signals ,but are delayed therefrom .,bya

fBriefly, my invention resides in .causing the .time corresponding with Vthe ydistance `to the re- 'gate pulses of a pulse kecho system `to .beshown v,mote object. iCfurve VD .shows .the range "gate" Yfas adeiiectionalong theazimuthaxis ofthe cat hpulses which, for the particular case illustrated, ode ray tube screen rather `than Vas a luminous `correspond in .time with the 4received',pulses.A

radiating portion l1.

'radiating portion I'I to pass to receiver 8.

addition to these signals a further voltage is applied to indicate the azimuth of maximum radiation from the antenna in a manner described in further detail hereafter. For the case of the antenna at rest, this voltage is a constant voltage as shown in'curve E, Fig. 1.

The operation of my invention may be understood from the embodiment shown in Fig. 2. In the gure, a range sweep system I is illustrated, which provides a saw tooth voltage wave between vertical or range axis deflection plates 2 and 3 of cathode ray tube 4. This voltage causes the cathode ray beam to traverse the screen area successively along the vertical or range axis with substantially constant velocity. The Wave shape of signals generated inthe range sweep system corresponds to that shown in curve A, Fig. 1. Transmitter 5 produces an energy pulse each time range sweep system I causes the cathode ray beam to move across the screen. These pulses correspond in time with those shown in curve B, Fig. 1, and

' are applied to an antenna system, generally shown at 6. Range gate system 'I produces, as shown in curve D, Fig. 1, delayed voltage pulses in response to the transmitted signal, these pulses ben ing delayed by a time corresponding to `the ady justment of the range gate system. Reflected or reply pulses from remote objects appear at antenna system 6 and are applied to receiving system 8 which converts them to pulses of unidirectional electromotive force, as shown in curve C, Fig. 1, and applies them between control electrode 9 and the cathode of cathode ray tube 4,

` thereby intensifying the cathode ray beam andv producing a luminous spot on screen I0 at the instant the pulses arrive. The voltage from range sweep system I causes these spots to appear at a position along the vertical or range axis corresponding to the distance of the remote object causing the pulses.

Y In accordance with known practice, the range gate 'I may be manually controlled to adjust the time position of the range gate pulses, or as previously pointed out, these pulses may be automatically maintained in coincidence with the received pulses. Various range tracking systems for 4 accomplishing this adjustment are known to the art. Therefore, the range gate I is indicated only schematically as being controlled by range control I9. For automatic range tracking, the range control I9 is controlled by pulses from receiver 8 supplied over the conductor 20. For further details of a suitable range tracking system providing either manual or automatic positioning of range v gate pulses and accurate measurement of the corresponding ranges, reference may be made to the copending application Ser. No. 400,080 of William C. Hahn, filed June 27, 1941, and assigned to the same assignee as the present invention.

Another suitable range tracking system of this l type is also fully disclosed in Patent 2,467,208-

narrow axis in the azimuth direction, the position of the axis depending on the position of structure I'I. Gears or similar means are connected to radiating structure I1 to operate variable resistance ment of antenna 6.

I8 so that the resistance Value corresponds to the azimuth direction of maximum radiated power. The resistance of variable resistance IB is converted to a voltage in azimuth unit II so that the output voltage of this unit represents the direction radiating portion II is pointed, or oriented. When radiating portion I7 is stationary, this voltage is constant as shown in curve E, Fig. 1.

The total voltage output from azimuth system I I and range gate "I is applied to the horizontal or azimuth deflecting plates I2 and I3 of cathode ray device 4. The horizontal deection of the cathode ray beam, and consequently, the position of images on the tube screen then corresponds to the sum of these two voltages.

Fig. 3 shows the appearance of the cathode ray tube screen with radiator I1 stationary when the beam intensity is increased above normal and no signals are being received. The cathode ray beam then has a uniform intensity and produces a luminous line over thelength of the screen, the position of the line correspondingY to the adjust- I-Iowever, at one point I4 the line sharply deiiects tothe left, this deiiection corresponding to the signal from the range gate system which adds a delayed voltage pulse to the constant voltage of Fig. 1, curve E. In actual operation, however, only a relatively small number of remote objects will lie in the eld lof the antenna and the cathode ray tube screen will display only a small number -of luminous spots as shown in Fig. 4. It is evident from the gure that the line shown in Fig. 3 disappears and the only luminous spots on the screen correspond to received pulses from remote objects. These signals lie on a single vertical line corresponding to that shown in Fig. 3 with the exception of one signal I5 which is displaced to the left by the range gate signal.

It is evident from Fig. 4 that luminous point I5 is the point corresponding to the range gate" pulses. 1i the exact range of the remote object causing this spot is desired, the range gate pulse is adjusted either manually or automatically, by operation of range control I9, to show point I5 at a maximum displacement to the left, it being always apparent that the distance to the remote object causing spot I5 and no other is lbeing measured. If the pulse echo system is equipped with an automatic range system, it is obvious from inspection of the cathode ray tube screen that luminous point I5 corresponds to the remote object whose distance is being measured and that other points are not being utilized in the automatic measuring system- This enables the operator to select readily the luminous point corresponding to the remote object whose distance is automatically being measured and prevents any possible confusion relative to the exact position of the range gate pulse on the cathode ray tube screen.

While I have shown and described my invention as applied to a particular system of connections and as embodying various devices diagrammatically shown, it will be obvious to those skilled in the art that changes and modications may be made without departing from my invention, and I, therefore, aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a pulse echo system, a directive wave emitting device, a transmitter arranged to supply recurrent energy pulses to said device to. be emitted thereby, a cathode ray device having a.

viewing screen, a receiver responsive to energy pulses from remote objects in the path of energy from said emitting device, rst means to vary the intensity of the electron ray of said cathode ray device in accordance with pulses received at said receiver, second means to deflect said ray in one direction across said screen during a predetermined interval after each energy pulse from said emitting device, third means to produce voltage pulses corresponding to said first pulses but delayed thereafter by a predetermined time interval, fourth means to produce a voltage corresponding to the orientation of said emitting device, and fth means to deect said ray in a, direction at right angles to said rst deflection in accordance with the total voltage of said third and fourth means, whereby pulses received from remote objects during pulses produced by said third means are indicated on said screen at a point out of alignment with the indications produced by pulses received from other remote objects.

2. In a pulse echo system, a directive wave emitting device, a transmitter arranged to s'upply recurrent energy pulses to said device to be emitted thereby, a cathode ray device having a viewing screen, a receiver responsive to energy pulses from remote objects in the path of energy from said emitting device, rst means to vary the intensity of the electron ray of said cathode ray device in accordance with pulses received at said receiver, second means to deect said ray in one direction across said screen during a predetermined interval after each energy pulse from said emitting device, third means to produce voltage pulses corresponding to said energy pulses from said emitting device but delayed thereafter by a predetermined time interval, fourth means to produce a voltage corresponding to the orientation of said emitting device, fth means to deiiect said ray in a direction at right angles to said first deection in accordance with the total voltage of said third and fourth means, whereby pulses received from remote objects during pulses produced by said third means are indicated on said screen at a point out of alignment with the indications produced by pulses received from other remote objects, and sixth means responsive to selected energy pulses at said receiver corresponding to a particular remote object for controlling said third means to maintain said voltage pulses continuously in correspondence with said selected energy pulses.

3. In a pulse echo system, a wave emitting device, a transmitter arranged to supply recurrent energy pulses to said device to be emitted thereby, a cathode ray device having a viewing screen, a directive energy receiver responsive to energy pulses from objects in a particular portion of the path of energy from said emitting device, first means to vary the intensity of the electron ray of said cathode ray device in accordance with pulses at said receiver, second means to deect said ray in one direction across said screen during a predetermined interval after each energy pulse from said emitting device, third means to produce voltage pulses corresponding to said first energl7 pulses but delayed thereafter by a predetermined time interval, fourth means to produce a voltage corresponding to the orientation of said receiving device, and fifth means to deect said ray in a direction normal to said first deiiection in accordance with the total voltage of said third and fourth means, whereby pulses received from remote objects during pulses produced by said third means are indicated on said screen at a point out of alignment With the indication produced by pulses received from other remote objects.

4. The method of measuring the range of an energy reiiecting object characterized by the steps of transmitting a series of directional energy pulses, deflecting a ray beam in one direction in synchronism with said transmitted pulses, changing the intensity of said beam when a reflected pulse is received, generating voltage pulses delayed from said transmitted pulses by a predetermined time, generating a voltage corresponding to the direction of maximum energy of said transmitted pulses, and deflecting said ray beam in a direction at right angles to said first deflection in accordance with the total voltage of said voltage pulses and said voltage, whereby received signals corresponding in delay to said last pulses are shown in a displaced position with respect to other received signals.

HARRY F. MAYER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,415,981 Wolff Feb. 18, 1947 2,416,088 Deerhake Feb. 18, 1947 2,419,205 Feldman Apr. 22, 1947 2,419,239 White Apr. 22, 1947 2,422,361 Miller June 17, 1947 

